Process for making benzoyl halides



Patented July 2,1935 H w r UNITED STATES. PATENTF1O.FF'IC'E;Q

1 2,006,335 t v. I V "PROCESS FOR MAKING BENZOYLHALIDESJ. I

Courtney Conover, .St. Louis, Mo., assignor, by

mesne assignments, to Monsanto Chemical Company, a corporation of Delaware No Drawing. Application June 10, 1929' Serial-No. 369,933

" )7 Claims. (01. zoo- 123 This invention relates to themanufacture of to condense. The fixed gases may thereafter be benzoyl chloride and benzoyl bromide; according separated by scrubbingiwith watergas is well to which ortho phthalic anhydride is caused to understood by those skilled in the art. v v combine with a substantially dry hydrogen halide Although the preferred temperature range for a elevated t p u es a d pref rab y in the batch operation is represented as" being in the 5 presence of anhalogen carrying agent, which is neighborhood of 300 C., the reaction maybe concapable of stimulating the reaction between the ducted at'widely different temperatures depend phthalic anhydride and the hydrogen halide. ing to'a certain extent upon the catalyst and rang- One object of the invention is to provide a ing from 200C. upwardly. Obviously, when the 10 novel method of synthesizing the particular phthalic anhydride is caused to react in a liquid 10 benzoyl derivatives, which utilizes inexpensive raw state, a pressure greater than the partial pressure materials and avoids the problem of disposing of of the phthalic anhydride at the particular temby-produots. perature is maintained.

Another object of the invention is to provide a It is to be noted, however, that the invention is method of manufacturing benzoyl halides, which not restricted to liquid phase operation. Similar- 15 is suspeotible to continuous operation requiring ly, the invention is not restricted to a batch type but little attention and avoiding the necessity of of operation. I have found for example that one expensive synthesizing ingredients. may advantageously cause phthalic anhydride Heretofore benzoyl chloride has been made by and hydrogen chloride to flow in parallel or causing benzoic acid to react with phosphorous counter-current fashion through areacting tower 20 pentachloride. According to other processes, containing the desired halogen carrying agent, which have been suggested, the product is presuch for example as chromium chloride. It is to pared from benzaldehyde, from benzotrichloride be noted too that activating agents other than and from benzene. Uniformly, however, these anhydrous chromium chloride may be employed processes have not been satisfactory, either befor example, chromium or zinc chlorides, oxy- 25 cause the yield is low, manufacturing conditions chlorides, oxides and analogous compounds may difiicult to maintain, or too expensive. As a rebe substituted. The activating materials "prob-.

- sult, use of the benzoyl chloride in commerce has ably undergo some change in the course of the been restricted and the production of this mareaction and forthis reason my invention is not terial comparatively small. By my invention, the limited to the addition of aparticular material 30 disadvantages of the former process are obas an initial activating ingredient; Although. viated, and one is able to obtain good yields of combined chromium is my preferred activating high grade product even with starting materials ingredient and has been found to stimulate the of inferior quality. reaction to a highly favorable equilibrium ratio,

According to one embodiment of my invention, the invention is not limited to the use of this in- 5 I mix approximately 100 pounds of phthalic angredient, since other conditions will afford satishydride with about four pounds of chromium factory yields, which are based: upon the broad chloride and heat the same to a temperature just conception of reacting hydrogen chloride with below the boiling point of the anhydride. Adortho phthalic anhydride. v e w 40 vantageously the air in the container is displaced The reaction is best performed in the absence 40 by introducing dry hydrogen chloride before the of waterthat is, in a state which is substancharge is heated. Subsequently and while the tially anhydrous. Myexperiments indicate, howcharge is agitated vigorously, hydrogen chloride ever, that a small amount of water is not objecis introduced immediately above or just below tionable andin fact probably takes part in the re- 7 the surface of the molten mass at a rate of about action. However, the amount necessary is so 45 three pounds of gas per' hour. A temperature small that the ingredients employed will be found between 290 and 300 and a pressure of from 5 to cofitain sufiicient moisture to supplythe reto 20 pounds per square inch are maintained. quirement. Large excesses of water at the tem- The vapors which are released from the conperatures of thereaction tend to promote the tainer comprises benzoyl chloride, phthalic anformation of, benzoic acid, which, of course, will 50 hydride, carbon dioxide and hydrogen chloride. reduce the yield and make the isolation of the An initial cooling of this mixture results in the desired product more difficult. separation of most of the phthalic anhydride; Although I have specified a definite set of confurther cooling causes the remaining portion of ditions under which the reaction takes place in 5 the phthalic anhydride and the benzoyl chloride its preferred form, and have indicated briefly'55 the tendency which may be expected upon changing these conditions, it is to be understood that many other changes may be practiced without I departing from the spirit of my invention, and

of a decarboxylating catalystat a temperature above 200 C. while avoiding pyrolytic dcoinposi tion.

2. The method of manufacturing benzoylchlo ride that comprises causing phthali'c aril'iydrlde when in a fluid state to react with substantially dry hydrogen chloride in the presence of an inorganic activating agent at a temperature above 200 C. while avoiding pyrolytic decomposition: =..'II 1161 99 of. manuwt r n .931. .1 ride th t. emnri esp sinaphth q an q to react under substantiallyanhydrous conditions mmhxdr sen hlpq ibl ih p s e f e l lxt a ent, emb d n a me l s l a Em tmsa .90 Q- .wh v eia id ngw r ly w def a. e asures s fi ient to m tain the phthalic anhydride in a liquid phase.

peratur'es above 200 C. while avoiding pyrolytic 4. The method of manufacturing benzoyl chloride, that comprises causing phthalic anhydride when in a fluid state to react under substantially anhydrous conditions with hydrogen chloride in the presence of a catalyst containing a compound of chromium at a temperature above 200 C. while avoiding pyrolytic decomposition.

5. The method of manufacturing benzoyl chloride that comprises causing phthalic anhydride to react under substantially anhydrous conditions with hydrogen chloride at a temperature of approximately 200-300 C. inthe presence of chrom'iuxii chloride.

6. The methodof manufacturing benzoyl chloride that comprises causing phthalic anhydride andhy'drogeii chloride to move continuously in a counter current manner with respect to each decomposition.

7. The method of manufacturing benzoyl chloride which consists in reacting phthalic anh'ydride COURTNEY conovna 

